Apparatus for use in the seeding of clouds



Oct. 8, 1968 D'AVIGNON 3,404,821

APPARATUS FOR USE IN THE SEEDING OF CLOUDS Filed April 21, 1966 INVENTOR Jacques D'AVIGNON ATTORNEY United States Patent 3,404,821 APPARATUS FOR USE IN THE SEEDING 0F CLOUDS I Jacques dAvignon, Repentigny, Quebec, Canada, assignor to Weather Engineering Corporation of Canada, Ltd., Dorval, Quebec, Canada Filed Apr. 21, 1966, Ser. No. 544,231 Claims priority, application Canada, Apr. 30, 1965, 929,609 7 Claims. (Cl. 226-90) ABSTRACT OF THE DISCLOSURE A feeding apparatus for feeding a soft cord including a driven toothed roller having parallel, circumferential rows of gear teeth forming a gripping nip with a spring urged grooved roller.

This invention relates to apparatus for use in the seeding of clouds for the purpose of modifying the weather.

One method of modifying precipitation has been to disperse some chemical, for example silver iodide, into the atmosphere. This has the effect of causing freezing of super-cooled cloud droplets thereby initiating the snow crystal growth process. However, this method involves an inherent problem in that it is diflicult to regulate the formation of the silver iodide crystals so as to produce proper numbers of crystals of a type which are active in crystallizing cloud droplets.

To solve this problem it has been proposed to seed clouds by continuously feeding a chemical nucleating agent impregnated cord of combustible material simultaneously with a combustion gas and an oxygen containing gas under forced draft to a combustion zone to sustain combustion at a temperature of at least 2600 F. thereby to burn the cord and to vaporize and recrystallize the nucleating agent and to cause it to disperse into the atmosphere. The gas mixture is preferably induced into the combustion zone in a direction such as to cause a swirling motion of the flame about the zone.

An apparatus suitable for carrying out this process has also been proposed, the apparatus including a fire-pot having a refractory base and an upwardly extending cylindrical refractory lined wall terminating in an open upper end and serving as a flue. The wall has a feed opening for introducing gas at an angle to provide a swirling motion and the nucleating agent in continuous form, that is, in the form of a cord, is fed into the fire-pot through the same opening. A feed tube connects the feed opening with a source of combustible gas and an oxygen containing gas and is connected to a blower. The feed tube for the cord joins the gas feed tube near the fire-pot so that the cord may be fed through the feed opening with the gas, sufficient clearance being provided for this purpose between thewall of the tube and the cord, as described in assignees US. patent to Robert F. Power et al., 3,357,926, issued Dec. 12, 1967.

The present invention relates specifically to an arrangement for feeding the cord to the fire-pot at a controlled rate. Previously, the means provided has been such that there was a tendency for the cord to slip with respect to the feed means so that the cord under some circumstances was fed into the fire-pot at too slow a rate with the result that insuflicient numbers of iodide crystals were dispersed into the atmosphere. A further difliculty arose from the fact that the surface properties of the cord are not unitforin, that is to say, one part of the cord may be relatively smooth and another part relatively rough. The heretofore proposed feeding means which operated mainly as a result of friction between the cord and the feeding means, thus fed the cord into the fire-pot at an uneven rate 3,404,821 Patented Oct. 8 1968 dependent on these surface properties and it was diffi cult to adjust the crystal output 'of the apparatus at'the desired level. v v In accordance withthe present invention there is provided an arrangement for feeding a cord into the fire-pot of an apparatus for producing cloud seeding crystals, the arrangement including a pair of rollers having peripheral surfaces which define a nip. The cord is gripped by the rollers and fed forward in a positive manner to the firepot Preferably, one of the rollers has pronounced teeth and can be in the form of a gear wheel and the other roller has a shallow, peripheral groove in which the cord is located. The roller with the pronounced teeth is driven, for example, by means of an electric motor.

In the present application, silver iodide was used as th" nucleating agent impregnated in the cord.

Having now generally described the invention the same will be explained in more detail with reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of a silver iodide cord feed arrangement in accordance with the present invention;

FIGURE 2 is a top plan view of the arrangement of FIGURE 1;

FIGURE 3 is a further perspective view of th arrangement of FIGURE 1, and

FIGURE 4 is a vertical section on the line FIGURE 2.

The silver iodide cord feeding arrangement includes-a base plate generally indicated at 10 which is in the form of an angle member having a horizontal flange 11 and an upright flange 12. The flange 11 is adapted to be secured by means of bolts to'the inside surface of the bottom of a container which houses the cloud seeding apparatus. A substantially horizontal lever 13 is pivotally mounted on the flange 12 at 14. The other end of the lever 13 is curved into a semi-circular shape as can be seen from FIGURE 2 and has an aperture therein adapted to receive a book 15 at the lower end of a traction spr'ing 16, the upper end of the traction spring 16 being secured to a finger 17 projecting from the flange 12.

The lever 13 carries an angle or bracket 18 which projects laterally of the lever 13 and then parallel therewith to form a fork, the two arms of which serve to mount a spindle 19. A roller 20 having a shallow, peripheral groove is rotatably mounted on the spindle 19.

At a location immediately above thez roller 20 there is provided a drive roller 21 in the form of a gear wheel which is mounted on a shaft 22. An electric motor 23 is mounted on the side of the flange 12 remote from the gear wheel 21 and the shaft 22 is the output shaft, or is connected to the output shaft, of the motor 23.

The gear wheel constituting the roller 21 has its teeth arranged in three rows and can readily be produced by making two lathe cuts through the teeth of a standard gear. The rows of teeth ensure satisfactory feed action and a gear having two rows of teeth has been found to be suitable. The diameter of the gear can vary from about A diameter to about diameter, and the gear teeth should not be too rounded at the ends otherwise the gear proves to be unsatisfactory for the intended purpose.

A guide ring 24 (see particularly FIGURES 1 and 3) is mounted on the part of the bracket 18 which extends laterally of the lever 13 and is located at a position'which is in substantially the same horizontal plane as the nip between the rollers 20 and 21.

The illustrated arrangement serves to feed a silver iodide cord, generally indicated at C (FIGURES 2 and 4), into the bell-shaped mouth of a tube 25 which itself leads directly to the fire-pot of the cloud seeding apparatus.

In use of the arrangement illustrated the cord C is fed, from a supply source such as a reel, through the ring 24, then through the nip between the rollers 20 and 21 and entered in the mouth of the tube 25. To facilitate entry of the cord between the rollers 20 and 21 it is possible to swing the lever 13 downwardly about the pivotal mounting 14 and against the action of the spring 15 thereby to separate the roller from the roller 21. Immediately the lever 13 is released, it returns to the illustrated position in which the spring 16 biases the lever 13 and hence the roller 20 upwardly so that the part of the cord between the rollers 20 and 21 is positively gripped by these two components. Upon energization of the motor 23 the roller 21 turns and its teeth feed the cord C positively into the mouth of the tube 25, and thence to the fire-pot, the roller 20 acting as a resilient backing member to insure that there is no slipping between the teeth of the gear or roller 21 and the cord C. In addition the groove in the roller 20 prevents any wander of the cord axially of the rollers so that any tendency for the cord to be disengaged from the rollers 20 and 21 is resisted. The ring 24 also assists in preventing wander.

Thus, the rate at which the cord C is fed to the fire-pot depends only upon the rate of rotation of the roller 21 and is very little influenced by the surface roughness or other characteristics of the cord C. By suitable adjustment of the input voltage to the motor 23 it is possible to vary the rate at which the cord is fed whereby close control of the rate of crystallization of the silver iodide can be affected. Thus there are no periods of silver iodide starvation or any periods where there is an excess of silver diodide.

According to one preferred embodiment the roller 20 has a diameter of /2" and the diameter of the roller or gear 21 is A". In other words, the ratio of the diameter of the roller 20 to the diameter of the roller 21 is in the ratio of 2: 1.

According to another preferred embodiment the gear has 42 teeth arranged in three rows of 14 teeth as is produced, as described above, by lathe cutting the teeth of a standard gear. This gear has a diameter of A5" and in conjunction with a 1 r.p.m. motor feeds approximately four feet of cord per hour. To vary the rate of cord the speed of the motor is adjusted.

I claim:

1. An arrangement for feeding a nucleating agent impregnated cord to a fire-pot of a cloud seeding device, comprising a base plate, a forked lever on one side of said plate, means pivotally mounting one end of said lever on said base plate, a forked part of said lever having parallel arms, a spindle carried by said arms, a rotatable roller mounted on said spindle, a shaft mounted on said base plate, a toothed gear wheel mounted on said shaft at a location immediately adjacent said roller, the roller and the gear wheel being arranged to form a nip,'drive means for rotating said shaft, and spring means operatively connected between said lever and said base plate normally biasing said lever in a direction which brings said roller towards said gear wheel for gripping a nucleating agent impregnated cord entered in the nip.

2. An arrangement according to claim 1 in which the peripheral surface of said roller has a shallow, U-shaped groove therein adapted to receive and guide said cord.

3. An arrangement according to claim 1 in which said gear Wheel has circumferentially extending, parallel rows of teeth.

4. An arrangement according to claim 1 in which said gear wheel has two circumferentially extending, parallel rows of teeth.

5. An arrangement according to claim 1 in which said gear wheel has three circumferentially extending, parallel rows of teeth.

6. An arrangement according to claim 1 in which said gear wheel has circumferentially extending, parallel rows of teeth produced by making at least one lathe cut through the teeth of a gear initially having a single circumferentially extending row of teeth.

7. The structure as claimed in claim 1 in which said lever includes guide means in substantial alignment with said roller and gear for receiving a portion of cord, downstream of said roller and gear and guiding it toward said nip.

References Cited UNITED STATES PATENTS 1,096,857 5/1914 Pederquist 226-187 3,251,341 5/1966 Eburn et al. 226187 X ALLEN N. KNOWLES, Primary Examiner. 

